The recent passage of the Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008, which requires private health plans to provide equal coverage of behavioral and medical/surgical services, also known as parity, represents an important step in the expansion of access to substance abuse and mental health treatment. The new law will create an opportunity for new funding for behavioral health services, and it will likely launch a significant restructuring of private and public insurance coverage for behavioral health treatments. In fact, the new legislation may have its largest public health impact through its indirect influence on the State Children's Health Insurance Program (SCHIP), public health insurance coverage for children under 20 not income-eligible for Medicaid. SCHIP enrollees suffer behavioral health problems at higher rates than in the overall child population, like their counterparts on Medicaid. However, SCHIP programs tend to limit coverage of behavioral health treatment through visit/day limits, high co-payments, coinsurance, and deductibles in ways that Medicaid programs do not. Federal parity legislation is especially significant for many SCHIP programs because these states meet federal SCHIP benefit requirements by benchmarking behavioral health benefits against private insurance plans directly affected by the new law. Thus, the new legislation creates a natural experiment by effectively inducing changes in benefit design, and likely changes in the management of behavioral health services in some SCHIP programs, while leaving other programs that do not benchmark benefits in this way unchanged. The effect of this legislation on access to substance abuse and mental health services was further strengthened by the reauthorization of SCHIP in February of 2009, both because it expands the scope of the program with additional funding, and because it requires parity. We propose to exploit the variation created by new federal parity legislation to pursue three aims. 1) to examine how SCHIP programs change behavioral health benefit design and management approaches in response to changes in benchmark plans induced by parity legislation;and 2) to estimate changes in SCHIP coverage, utilization and out of pocket spending for child behavioral health services (Aim 2) among likely SCHIP enrollees in affected states following the implementation of new federal parity legislation. We will pursue these aims with primary data collection regarding benefit design and management features of state SCHIP programs before and after the law change (Aim 1). Second, we will survey parents regarding substance abuse and mental health service use and related outcomes among children aged 3 to 17 before the law change takes effect and 12 months after the law change (Aim 2). We will analyze these new data using appropriate panel data methods to account for repeated observations on individuals, and using estimation strategies such as generalized Poisson or negative binomial models for count data and generalized linear models to address spending data, which are often highly skewed.